It depends upon what part is biggest restriction to air flow. That intake they used definitely was not the restriction. As far as 50% throttle blade angle goes, I wonder how that translates to what percentage the restriction of max airflow is. That was pretty big throttle body in the video.
It might not translate to well to intake runner size the length of the restriction might come into play, it's probably more comparable to the carb. I guess the importance of restriction is head than intake then carb.